Abstract

PURPOSE: We assessed patient outcomes using 2 widely different contemporary lithotripters.MATERIALS AND METHODS: We performed a consecutive case series study of 355 patients in a large private practice group using a Modulith® SLX electromagnetic lithotripter in 200 patients and a LithoGold LG-380 electrohydraulic lithotripter (TRT, Woodstock, Georgia) in 155. Patients were followed at approximately 2 weeks. All preoperative and postoperative films were reviewed blindly by a dedicated genitourinary radiologist. The stone-free rate was defined as no residual fragments remaining after a single session of shock wave lithotripsy without an ancillary procedure.RESULTS: Patients with multiple stones were excluded from analysis, leaving 76 and 142 treated with electrohydraulic and electromagnetic lithotripsy, respectively. The stone-free rate was similar for the electrohydraulic and electromagnetic lithotripters (29 of 76 patients or 38.2% and 69 of 142 or 48.6%, p = 0.15) with no difference in the stone-free outcome for renal stones (20 of 45 or 44.4% and 33of 66 or 50%, p = 0.70) or ureteral stones (9 of 31 or 29% and 36 of 76 or 47.4%, respectively, p = 0.08). The percent of stones that did not break was similar for the electrohydraulic and electromagnetic devices (10 of 76 patients or 13.2% and 23 of 142 or 16.2%) and ureteroscopy was the most common ancillary procedure (18 of 22 or 81.8% and 30 of 40 or 75%, respectively). The overall mean number of procedures performed in patients in the 2 groups was similar (1.7 and 1.5, respectively).CONCLUSIONS: We present lithotripsy outcomes in the setting of a suburban urology practice. Stone-free rates were modest using shock wave lithotripsy alone but access to ureteroscopyprovided satisfactory outcomes overall. Although the acoustic characteristics of the electrohydraulic and electromagnetic lithotripters differ substantially, outcomes with these 2 machines were similar.

Commentaires
1

This is a remarkable publication: 355 patients were treated in a private practice group, the first 155 patients with the LithoGold LG-380 electrohydraulic lithotripter. “After this device was replaced 200 patients were treated with the Modulith SLX…”
As it is a consecutive case series one would assume that the patient characteristics did not differ in the two groups; but they obviously were different. After patients with multiple stones were excluded from analysis only app. 50% of the LG-380 patients but app. 70% of the Modulith SLX patients were finally evaluated.

Treatment with the SLX used the highest power Level (PL-9). ”The lithotripsy protocol was proposed by the Indiana University researchers.” Using the PL-9 with 60 SWs/min the group had previously shown in animal experiments with the SLX “highly focused region of tissue erosion largely devoid of recognizable renal structures”. (BA Connors et al. Evaluation of shock wave lithotripsy injury in the pig using a narrow focal zone lithotriptor. BJU Int. 2012 Nov;110(9):1376-85)
Unfortunately complications were not reported in the present clinical paper.

Other experiments by the same group suggested a better clinical fragmentation with the LG-380 as its wide focus “would not be much affected by 10mm of respiratory excursion. The same … would not hold true for the SLX. Although the SLX broke stones at the target point more effectively than … the LG-380 … the breakage efficiency of this narrow focal zone lithotripter fell off rapidly as the stones were moved laterally” (YA Pishchalnikov et al. Evaluation of the LithoGold LG-380 lithotripter: in vitro acoustic characterization and assessment of renal injury in the pig model. J Endourol. 2013 May;27(5):631-9).
One would expect that this would translate into a much smaller number of shocks with the LG-380 but the difference was only marginal though statistically different: mean number of shots: electrohydraulic 3,040 ± 196 vs. electromagnetic 3,270 ± 481, p

This is a remarkable publication: 355 patients were treated in a private practice group, the first 155 patients with the LithoGold LG-380 electrohydraulic lithotripter. “After this device was replaced 200 patients were treated with the Modulith SLX…”
As it is a consecutive case series one would assume that the patient characteristics did not differ in the two groups; but they obviously were different. After patients with multiple stones were excluded from analysis only app. 50% of the LG-380 patients but app. 70% of the Modulith SLX patients were finally evaluated.
Treatment with the SLX used the highest power Level (PL-9). ”The lithotripsy protocol was proposed by the Indiana University researchers.” Using the PL-9 with 60 SWs/min the group had previously shown in animal experiments with the SLX “highly focused region of tissue erosion largely devoid of recognizable renal structures”. (BA Connors et al. Evaluation of shock wave lithotripsy injury in the pig using a narrow focal zone lithotriptor. BJU Int. 2012 Nov;110(9):1376-85)
Unfortunately complications were not reported in the present clinical paper.
Other experiments by the same group suggested a better clinical fragmentation with the LG-380 as its wide focus “would not be much affected by 10mm of respiratory excursion. The same … would not hold true for the SLX. Although the SLX broke stones at the target point more effectively than … the LG-380 … the breakage efficiency of this narrow focal zone lithotripter fell off rapidly as the stones were moved laterally” (YA Pishchalnikov et al. Evaluation of the LithoGold LG-380 lithotripter: in vitro acoustic characterization and assessment of renal injury in the pig model. J Endourol. 2013 May;27(5):631-9).
One would expect that this would translate into a much smaller number of shocks with the LG-380 but the difference was only marginal though statistically different: mean number of shots: electrohydraulic 3,040 ± 196 vs. electromagnetic 3,270 ± 481, p